Polymorphism in ficolin-1 (FCN1) gene is associated with an earlier onset of type 1 diabetes mellitus in children and adolescents from northeast Brazil

Ficolins are innate immune proteins able to activate the complement system by the lectin pathway. Single nucleotide polymorphisms (SNPs) of FCN1 and FCN2 genes, encoding for ficolin 1 and 2, have been related to the susceptibility to infectious and autoimmune disease. This study aims at investigating the association of SNPs at FCN1 and FCN2 gene with the development of type 1 diabetes mellitus (T1D). Two SNPs at FCN1: rs2989727 and rs1071583 and three at FCN2: rs17514136, rs3124954 and rs7851696 were studied in 204 children diagnosed with T1D and 193 healthy individuals. No direct associations were found with the T1D onset or with the insurgence of T1D related celiac disease (CD) and autoimmune thyroiditis (AIDT). However, the genotype T/T (rs1071583) of FCN1 was associated with an early age at T1D diagnosis compared with C/C or C/T genotypes (p= 0.05), around two years of difference. Thus, our results suggest that the T/T genotype (rs1071583) is not directly involved in the initial steps of T1D onset, but, after the trigger that induces T1D, individual carrying this genotype could increase/accelerate the pancreatic autoimmune response.